Method and apparatus for producing ore sinter



April 18, 1961 R. w. STRANG 2,930,527

METHOD AND APPARATUS FOR PRODUCING ORE SINTER 5 Sheets-Sheet 1 Filed Feb. 15, 1958 r v I "1 1V /6 Q Q I7 4 33/ 17 Q E l J L J INVENTOR April 18, 1961 R. w. STRANG METHOD AND APPARATUS FOR PRODUCING ORE SINTER Filed Feb. 15, 1958 5 Sheets-Sheet 2 AWAR April 18, 1961 R. w. STRANG METHOD AND APPARATUS FOR PRODUCING ORE SINTER Filed. Feb 13, 1958 5 Sheets-Sheet 3 INVENTOR ATTORNEY April 18, 1961 R. w. STRANG 2,980,527

METHOD AND APPARATUS FOR PRODUCING oRE SINTER Filed Feb. 13, 1958 5 Sheets-Sheet 4 INVENTOR ORNEY April 18, 1961 R. w. STRANG METHOD AND APPARATUS FOR PRODUCING ORE SINTER Filed Feb. 15, 1958 5 Sheets-Sheet 5 INVENTOR Rope/(7' 14/ J'r/MM; BY i r ATTORNEY United States i 2,980,527 Mnr rion ArPARArUs non mionUcING one SINTER Robert W. Strang, 103 S. Patton Drive,- Coraopolis, Pa. Filed Feb. 13, 1958 Ser. No. 714,99? 7 Claims; (or; 7's sj This invention relates to apparatus and meth'oId' for producing ore sinter. More particularly, thisf invention relates to sintering apparatus of the pan type for the continuous production of ore sinter from ore fines or metallic oxides for charging into blast furnaces and to the method whereby this ore sinter is produced. I

In certain of the continuous type ore sintering apparati and methods in prior use in the art, a traveling conveyor or linkage was used to carry the sintering pairs. The fact that such conveyors or linkages could; not operate without attendant small shocks and bumps before a'nd during the sintering process was a great disadvantage, because any shock or bump during the sintering process is very apt to crack or shatter the sinter cake already formed. This invariably results in a very low q'aulityin the remaining material subsequently sintered, because the craking or shattering of the sinter cake already formed permits unequal and concentrated heating of the remaining mix. I

In practically all of the pan type ore sintering apparati and methods in prior use in the art a considerable time lag occurred while a particular sintering p'an was being removed from the sintering station, dumped, re

charged with bedding and sinter mix, and returned to the sintering station. During this time lag, or at least a con;- siderable portion thereof, the vacated sintering station i'Is unoccupied, thereby causing an attendant loss of earciency and production.

Also, all of the ore sintering apparati in use in Ith'e art comprise extensive installation of relatively massive apparati disposed in a basically horizontal order. Su'ch an installation in the typical situs of a congested mill area occupies an inordinate amount of space. Further, if expansion of the sintering plant becomes desirable the only recourse has been to extend the existing plant horizontally if there is space therefor, or to find a difie'rent situs for a new installation with the same horizontal disposition. I I I I I I Therefore, one object of my invention is to provide an apparatus and method for pan sintering ore finesin which the sintering pans are handled so that during the sintering, they are subjected to no possible bumps or shocks.

A further object of my invention is to provide an apparatus and method for pan sintering ore' fin'es in which the length of time for which any sinterin gstation is unoccupied and inoperative is minimal. I I I A still further object of my invention is to provide an apparatus for pan sintering orefines whichbccupies" a minimum amount of plant space. II II I II I Still further objects and advantages of my invention will be apparent from the following description aid the appended claims. I I

To describe the apparatus and method embodyirigrny invention, I provide a pan type ore sintering plant in which the sintering stations are vertically disposed one over the other, each having its own igniter and suction exhaust. The materials for the sinter mix' comprising mainly ore fines, coal, coke, and limestone or burnt lime 2 pass by gravity from their respective hoppers through a blade type mixer, where water is added, and into the sinter mix receiving hopper from which it is conveyed to the sinter mix charging hopper located over the charging station. The bedding o-r grate covering .i-naterial, which may be either sinter, lump ore, or crushed limestone, is deposited in the grate covering receiving hopper from which it is conveyed to the grate covering charging hopper which is also located over the charging station and adjacent the sinter mix charging hopper. II The sintering pan to be charged passes on a driven roller bed beneath the discharge spouts of the grate covering hopper and the sinter mix hopper respectively and is charged with bedding or grate covering material and sinter mix thereupon, and the excess of the sinter mix charge is scraped off by a pre-set scraper which levels the charged sinter mix approximately flush with the top of the sintering pan. The charged sintering pan their passes directly onto the driven roller bed of the chargingele vator and, is raised to the sintering station to be occupied. At the same time the drivenroller bed on the discharge elevatoris moved to the same station to receive the pan of finished sinter occupying that station.

Each sintering station also has its own driven roller bed which receives and supports the sintering pan during sintering With the driven roller beds of the charging and discharge elevators in position, the finished pail of sinter is moved, by the driven rolls, onto the discharge elevator and, at the same time, the newly charged sinter pan is similarly moved from the charging elevatorin'to the sintering station just vacated. Thereupon, the finished pan of sinter is carried, by the discharging elevator, to the pan dumping station and is moved thereinto by driven rolls and dumped.

From-the dumping station the finished sinter progresses by gravity to a crusher where the sinter cake is crushed to a desirable size for charging into a blast furnace. After passing through the crusher, the sinter falls onto a shaker screen and the majority of the sinter, being of proper size, remains on top of the inclined screen and travels thereupon to a conveyor for disposition either to a cooler and storage or directly into a blast furnace. That small portion of the sinter which is undersize, the fines and the grate covering materials, fall through the screen and are collected and returned to the grate co've'ririg charging hopper for reuse.

This cycle is then repeated, the next sintering pan to be charged having been placed in the charging station by the discharge elevator before it moved to the sinter ing station which was charged in the preceding cycle. Obviously then there is one more sintering pain in the apparatus than there are sintering stations; that is to say, with all of the sintering stations occupied, as in normal operation, there is one sintering pan being charged with grate covering material and sinter mix to take its place in a sintering station in the next cycle as described.

In certain instances it is desirable to provide for an other position in the apparatus embodying my invention to increase its versatility as described hereinafter. For this purpose, in one modification of my invention, I, provide' an additional station directly opposite the pan dump ing station. This additional station is provided with a driven roller bed but has no suction exhaust or igniter since it is not a sintering station. In this modification of my invention, I have also provided, at this station, a retractable or pivotal roller bed which acts as a crossover between this station and the pan dumping station when the roller bed of the dicharge elevator is not in aligned position with that station. This facilitates the use of; thefldischarge elevator for its other appointed purposes in the operationof my apparatus. In addition, this cross-over makes it possible to operate my apparatus in 2,980,152? g a H a relatively eflicientrnanner in the event that either the charging or the discharge elevator should have to be shut down for repairs. Further, this station provides a convenient position for making repairs to pans which may be injured or deteriorated in service.

Each sintering station in my apparatus has its. own suction exhaust and dust collector. It will be obvious that more than one sintering station can be served by a single dust collector, but I have found that the operation of my apparatus is more efiicient when a dust collector is provided to serve each sintering station.

It will be noted that, because the sintering pans of my apparatus are rolled horizontally into the sintering stations, the suction exhaust connection at eachsintering station must be accomplished after the sintering pan is positioned in the sintering station, and the said connec tion must be broken before the sintering pan is moved out of the sintering station. On this account, I have. terminated the suction exhaust pipe extending to each sintering station slightly below the level of the suction exhaust extension on the bottom of each sintering pan. In one form of sealing means for my apparatus, after the sintering pan is approximately in position, the gap between these two sections of the suction exhaust system is sealed by the application of two semi-circular closure bands which are pressed against the opening by extendable and retractable holding rods which are motivated by air cylinders. Hydraulic or electrical motivating means for the said holding rods may be substituted for these air cylinders, but I have found the air cylinders to be the mostsatisfactory both from the standpoint of operation and the availability of the supply.

In a more preferable form of sealing means for the suction exhaust connection I provide a basically cylindrical bellows surrounding the upper portion of the fixed section of the suction exhaust. The lower extremity of the said bellows is tightly engaged with a flange which in turn is rigidly engaged with the fixed portion of the suction exhaust, while the upper extremity is tightly engaged with a flange which is slidably engaged with the fixed portion of the suction exhaust. When the sintering pan is in position for connection the said slidable flange is moved upward and extends the bellows until the said flange has surrounded the portion of the suction exhaust appended from the sintering pan and has come to bear firmly against a flange thereon. Of course, in this arrangement, the fixed portion of the suction exhaust and the slidable flange are both of somewhat larger diameter than the portion of the suction exhaust appended from the sintering pan, thereby facilitating a satisfactory seal without the necessity for perfectly aligning the sintering pan over the fixed portion of the suction exhaust. There are many ways by which the movement of the said slidable flange and bellows can be accomplished but the means I have found most simple and efficient is a forked lever, the forked ends of which embrace and movably engage the slidable flange while the other extremity is motivated by the piston from a single air cylinder.

Referring now to the drawings:

Fig. I is a cross-sectional plan view showing the charging and discharge elevators aligned with a sintering station and the dumping station and is taken in the plane of section line II of Fig. II.

Fig. II is a cross-sectional view through the sintering plant and taken in the plane of section line 11-11 of Fig. I.

Fig. III is a cross-sectional view through thesintering plant showing the serving the sintering stations and taken in the plane of section line III-III of Fig. I.

'Fig. IV is a combined elevational and cross-sectional iew and taken in the plane of section line IVIV of ig. I.

Fig. I is a cross-sectional view through the suction exhaust extension on the bottom of 6 f y sintering arrangement of the dust collectors 4 pans showing the semi-circular closure bands of one form of sealing means for my apparatus in the sealing position and taken in the plane of section line V-V of Fig. VI.

Fig. VI is an elevational view of the suction exhaust connection below one of my sintering pans showing the semi-circular closure bands of one form of sealing means for my apparatus in withdrawn position and taken in the plane of section line VIVI of Fig. V.

Fig. VII is a partial cross-sectional view through the pivotal section or cross-over which I have provided in one modification of my invention at the dumping station.

Fig. VIIIis a fragmentary plan View showing the piv otal arrangement of the cross-over shown in Fig. VII and taken in the plane of section line VIII-VIII of Fig. VII.

Fig. IX is a ores-sectional view through a modified arrangement of the suction exhaust connection below one of my sintering pans showing the closure means in sealed position and taken in the plane of section line IX--IX of Fig. X.

Fig. X is an elevational view of the modified arrangement of the suction exhaust connection depicted in Fig. IX, showing the closure means in retracted, unsealed position and taken in the plane of section line X--X of Fig. IX.

Fig. XI is a plan view of the igniter and supporting structure therefor at one of the sintering stations.

Fig. XII is a partial cross-sectional view through a portion of the supporting structure of the igniter and taken in the plane of section line XII-XII of Fig. XI.

Fig. XIII is a cross-sectional view through the side of an igniter and sinter pan and taken in the plane of section line XIII-XIII of Fig. XI.

The numeral 1 refers to a side dump car carrying the raw materials for the sinter mix to their respective hopper 2. From the raw material hoppers the materials flow by gravity to the blade-type mixer 3, where they are mixed and the proper amount of .moisture added, and the sinter mix is distributed thereby to the sinter mix receiving hopper 4. From the hopper 4 the sinter mix is carried by conveyor 5 to the sinter mix charging hopper 6 in the pan loading station. The grate covering material is conveyed from the grate covering receiving hopper 7 by the conveyor 8' to the grate covering charging hopper 9. The sintering pan 10 is carried to the pan loading station by'the discharging elevator 11 and is driven through the pan loading station by roller bed 12. As the sintering pan 10 passes through the pan loading station the grate covering material is deposited therein ahead of the sinter mix and the excess of the sinter mix is scraped ofl by means of the scraper 13 and falls into the over flowhopper 14. From'time to time the collected overflow is removed from the overflow-hopper 14- and carried by means of the conveyor 15 and an elevator (not shown on the drawings) to the sinter mix charging hopper 6 for reuse. The roller bed of the charging elevator 16, having previously been moved to the pin loading station, receives the charged sintering pan 10 and carries it to the elevation of the sintering station to be occupied. The roller bed of the discharging elevator 11 is also moved to the same sintering station and when both the charging elevator 16 and the discharging elevator 11 have been moved to the proper positions opposite the roller bed 17 of the sintering station to be charged the air cylinders 18 are operated to withdraw the semi-circular closure bands 19. Then the roller beds 11, 16 and 17 of the discharging elevator, charging elevator and the sintering station being charged respectively are put in motion and the pan of finished sinter is moved onto the discharging elevator 11 while the pan of sinter mix is moved into the sintering station. The air cylinders 18 are immediately. activated to extend the closure bands 19 to closed position and at the same time the igniter 21 is lowered to reduce the airflow space around the top of the sintering t. pan during the ignition cycle. As soon as it has '"received the pan of finished sinter, the discharging elev'ator 11 proceeds to the level of the rotatably driven roller bed 22 of the dumping station where the pan of finished sinter is run onto the said roller bed 22 which is equipped with brackets 23 for holding the sintering pan during dumping. The roller bed 22 is rotatably driven by a gear box 24 and conventional motive means 25, and when it is inverted the finished sinter falls from the sinter pan 10 and descends therefrom to the crusher 26. After the sinter cake is crushed by passing through the crusher 26, it falls onto shaker screen 27 and the fines pass therethrough to conveyor 28 by which they are conveyed to a storage bin to be later used as grate covering material. The portion of the crushed sinter-cake which vibrates off the top of the shaker screen 27 flows by gravity or is conveyed to a conventional type cooler (not shown in the drawings) or is directly charged into a blast furnace.

Returning to the beginning of the sintering process; after the igniter 21 has ben lowered, the nozzles 53 of the igniter 21 are ignited and the combustion therefrom ignites the sinter mix. At the same time, the draft is drawn down through the sinter mix, along the suction offtake 29, through the dust collector 30 and through the fan 31 to exhaust stack 32. After the ignition of the surface of the sinter mix has been uniformly and completely accomplished, the combustion at the nozzles 53 of the igniter 21 is terminated and the igniter 21 is raised a predetermined distance to permit the proper airflowto sustain the ignition already established in the combustible portion of the sinter mix. The suction exhaust is continued. of course, thereby drawing the hot gases downward through the charged sinter mix in the sintering pan 10, and the sintering proceeds from the top of the mass downward with the sinter cake being formed progressively therethrough.

The dumping station, the crusher 26, and the shaker screen 27 are enclosed, insofar as possible, to enclose the dust therein, and this enclosure has a suction applied thereto to draw on the fines. This suction and the recovery of the fines is accomplished by the primary deduster 33 and the secondary de-duster 34.

In the modification of my invention in which I provide a cross-over at the elevation of the dumping station, the cross-over roller bed 35 is pivotally mounted on the structural columns which support the discharging elevator 11 and the sintering stations. The cross-over roller bed 35 is pivotally mounted on the outside flange of the said columns in such manner that when it is rotated upward to the unusable position, it will permit the discharging elevator ll-l to be raised to the elevation of the dumping station. Counter weights 36 are provided for the cross-over roller bed 35 and it may be rotated by cables or by other mechanically operative means. The rollers 37 of the cross-over roller bed, and of all of the other roller beds in my apparatus, are each driven rotatably by direct mechanical means of the electric type.

In the modified, and probably more desirable sealing means shown in Fig. IX and Fig. X of the drawings, the numeral 39 designates a basically cylindrical bellows, the skin of which comprises a fabric of impregnated asbestos or other heat resistant material, having relatively rigid rings 40 attached thereto at the folds thereof. The skin of the said bellows 39 is circumferentially attached at its lower extremity to the flange 41 which is firmly engaged with the suction exhaust pipe 29, and is circumferentially attached at its upper extremity to the flange 42 which is slidably engaged with the suction exhaust pipe 2?. The flange 42' is slidably operated in a vertical direction by the rollers 43 which are rotatably mounted on the forked lever 44 and the forked lever 44 is driven by a reversible air cylinder 45whicli is" rotatably attached to the driven arm thereof. The helical spring 46 is mounted above the slidable washer 47 to provi'dea spring load on the forked 1ever 44 and thus a constem sealing pressure is maintained as the slidable flange 42 is raised to its sealing position. The air cylinder 45 is pivotally mounted on the forked bracket 48 which is rigidly attached to the bracket 49. The said bracket 49 clampingly engages the suction exhaust pipe 29 and also forms the fulcrum for the forked lever 44. Therefore, the entire operating assembly for the sealing means comprises the rollers 43, lever 44, air cylinder 45, brackets 48, and 49, and is entirely supported on the suction exhaust pipe 29. When the sealing means used in this modification of my invention is in the closed or sealing position, the slidable flange 42 is pressed into firm engagement with flange 50 on the suctionexhaust extension of the sintering pan 10 thereby providing an effective seal. It should be noted that this sealing means has certain distinct advantages over that previously described; namely, in this sealing means the suction exhaust extension on the sintering pan 10 is smaller in diameter than the suction exhaust pipe 29 thereby eliminating the neces ity for perfectly aligning the sintering pan 10, and this sealing means employs only one air cylinder, or other type of operating means, whereas the sealing means previously described employs two.

Turning now to the igniters designated generally by the numeral 21, it will be understood that the said igniters 21, comprising a shell 5-1 lined with a refractory material 52 and having the burner nozzles 53 mounted in a grid pattern within the shell 51, niust be raised and lowered slightly to regulate the air flow differential between the igniting period and the sintering period. This regulation is accomplished as shown in Figs. XI and XII wherein a pivotally mounted air cylinder 54 operates coupledbellcranks 55 which in turn rotatably move eccentric torque tubes 56. The said torque tubes 56 are supported in bearings 57 attached to the structural framing for my apparatus and pass through bearings 58 which are rigidly attached to the shell 51 of the igniter 21. Certain other motive means may be substituted for the air cylinder, for instance a hydraulic cylinder or screw gear, however, I have found, as previously stated that the pneumatic means possesses greater advantages from the standpoint of ready control and easily available supply.

Fig. XIII is a fragmentary cross-section through the edge of the igniter 21 and the sintering pan 10 showing the sinter mix designated M resting on the bedding or grate covering designated B which is supported on the grating bars 59. In this view it is seen that the interior side plates 60 of the sintering pan 10 are disposed slantably inward toward the bottom. This insures a close seal at the edge of the sinter cake as it forms, shrinks and settles slightly in the sinter pan.

The sinter pans which I have chosen for use in my apparatus and method are approximately square in plan. If the dimensions of the p an are not approximately equal the sinter cake will crack during the sintering. On the other hand, if the pans are approximately square the sintering proceeds evenly and the cake shrinks away from the edges and settles without cracking. Because of this shrinkage and settling, the interior side plates of the sinter pans are disposed slantably inward toward the bottom, thereby insuring a close seal between the edge of the sinter cake and the sides of the sintering pan.

It must be understood that, although the pan dumping station is shown at the top station of the apparatus in the drawings showing this embodiment of my invention, this is not a strict limitation. On the contrary, the damping station may be placed at the elevation of any station above the ground level. This increases the versatility of the apparatus embodying my invention, for it makes possible the extension and enlargement of the apparatus upwards without regard to the position of the pan dump ing station. Of course, when the pan dumping station is not positioned opposite the uppermost sintering stal tion, thecross-ov'er, when one is provided, such men fication'must 'be ofa different type than that reviously assess? members, upon which the rollers are mounted, may be rotatably extended outward away from the space through which the discharging elevator travels.

The suction fans which I have shown in the accompanying drawings are of the type having two impellers mounted on the same shaft. Therefore, each unit serves two dust collectors as shown in Fig. III, with the olftake from each dust collector communicating with its separate impeller. I have found that, with the staggered arrangement of the dust collectors which I have shown in this embodiment of my invention, a conservation of space results from such a combination. However, this is not to be construed as a limitation for numerous other arrangements are possible within the scope of my invention.

It will be noted that I have provided driven roller beds for handling the sintering pans in the embodiment of my invention shown in the drawings and described hereinbefore. However, even though I consider this provision to be the most feasible and satisfactory, it must be realized that other means for accommodating the sintering pans could 'be provided without departing from the spirit of my invention. For instance, the charging station,

sintering stations, pan dumping station, the elevators and the cross-over, if one is provided, may be equipped with tracks, upon which the sintering pans may'be rollingly or slidingly accommodated and pushing means may be provided for moving the said pans thereon.

The embodiment of my invention, which I have shown .in the accompanying drawings, depicts nine'sintering sta- .tions. .strued as a limitation, for the apparatus may have more or less sintering stations so that the charging and discharging elevators are continuously operative. In other As indicated hereinbefore, this is not to be conwords, one in which the number of sintering stations is determined by the length of the sintering period and the capability of the elevators to supply and remove sintering pans will produce optimum results in respect of economy and continuity.

Obviously, once the sintering period for a given sinter -mix has been determined, an apparatus embodying the features of my invention can be readily adapted to automatic control means and a practically continuous supply of sinter cake can be afforded. This feature of my apparatus results in a significant economy in time and labor.

Attention must be given'to the proper addition of moisture to the sinter mix while it is being mixed in the blade type mixer.

Because of the possible differences in the qualities of the ingredients comprising the sinter mix, the amount of moisture which must be added can not be expressed in exact quantitative terms. However, I have found that the addition of approximately sixty percent (60%) of the moisture needed to convert the mix into a paste provides a mix which is readily workable and ignites and sinters uniformly.

The size of the ore particles used in my pan sintering process should preferably be approximately 0.12 inch,

.and the majority of the ore for the production of high iron content sinter should be from 0.06 inch to 0.25 inch. Too large a proportion of extremely fine particles detrirnentally decreases the suction, and too large a propor- 0.16 inch. x

The limestone or burnt lime, having a particle size of approximately 0.16 inch, causes an increase in the bond strength-of the sinter cake and, therefore, is beneficial to the process and product.

It will be obvious that the process described hereinbefore may be carried out substantially by any or all of the modifications of the apparatus embodying my. invention as set forth herein;

It should be understood that certain changes may be made in the arrangement set forth in the specification and shown in the drawings, it being understood that modifications in the precise embodiment of the invention may i be made within the scope of the following claims without departing from the spirit of the invention.

I claim as my invention:

1. An apparatus for producing ore sinter comprising a charging station, a plurality of sintering stations vertically disposed oneover the other and each of said sintering stations having an igniter and a suction exhaust connection, a charging. elevator communicating with the said charging station and each of the said sintering stations, a discharging elevator communicating with the charging station and each of the said sintering stations, a plurality of sintering pans each capable of being accommodated by the said sintering stations and the said charging and discharging elevators, and a pan dumping station adjacent the said. discharging elevator and communicating with the said discharging elevator.

2. An apparatus for producing ore sinter comprising a charging station having a driven roller bed thereunder, a plurality of sintering stations vertically disposed one over the other and each of said sintering stations having an igniter thereabove and a driven roller bed and a suction exhaust connection thereunder, a charging elevator communicating with the said charging station and each of the said sintering stations and having a driven roller bed thereon, a discharging elevator communicating with the charging station and each of the said sintering stations and having a driven roller bed thereon, a plurality of sintering pans each capable of being accommodated by the roller beds of the said charging station, the said sintering stations and the said charging and discharging elevators, and a pan dumping station adjacent to and communicating with the said discharging elevator and having a driven roller bed mounted rotatably about a horizontal axis.

3. An apparatus for producing ore sinter comprising a charging station having a driven roller bed thereunder, a plurality of sintering stations vertically disposed one over the other and each of said sintering stations having an igniter thereabove and a driven roller bed and a suction exhaust connection thereunder, suction means communicating with the said suction exhaust connection and affording a reduced pressure thereto, a charging elevator communicating with the said charging station and each of the said sintering stations and having a driven roller bed thereon, a discharging elevator communicating with the charging station and each of the said sintering stations and having a driven roller bed thereon, a plurality of sintering pans each capable of being accommodated by the roller beds of the said charging station, the said sintering stations and the said charging and discharging elevators, and a pan dumping station adjacent to and communicating with the said discharging elevator and having a driven roller bed mounted rotatably about a horizontal axis.

4. An ore sintering apparatus substantially as provided in claim 1, having a cross-over communicating between the pan dumping station and the vertically projected area of the sintering stations, which said cross-over is rotatably or pivotally mounted for clearance of the disthe pan dumping station and the vertically projected area of the sintering stations, which said cross-over has a driven roller bed thereon capable of accommodating the said sintering pans and is rotatably or pivotally mounted for clearance of the discharging elevator.

6. An ore sintering apparatus substantially as provided in claim 3, having a cross-over communicating between the pan dumping station and the vertically projected area of the sintering stations, which said cross-over has a driven roller bed thereon capable of accommodating the said sintering pans and is rotatably or pivotally mounted for clearance of the discharging elevator.

7. In the operation of an ore-sintering installation provided with a plurality of sintering stations disposed in vertically spaced relation, the method which comprises charging a moist mixture of ore fines, crushed coal, crushed coke, and crushed limestone into a sintering pan supported in a pan loading station, removing the loaded pan from said loading station and moving it vertically on one side of said vertical sequence of sintering stations into position adjacent to a selected one of the latter stations, moving the said loaded pan laterally into the selected station, uniformly igniting the coal and coke disposed in the upper surface of the charge while at the same time applying a suction to the lower extremity of the sintering pan and drawing the hot gases and air downward through the charge, discontinuing said ignition oi the charge, continuing the downward suction until substantially all of the coal and coke disposed in the charge has undergone combustion and a hard sinter cake has been formed in the sintering pan, discontinuing the said downward suction, removing the sinter-containing pan laterally and replacing the removed pan with a newly charged pan, transferring the removed pan of sinter vertically to a dumping station, and in the latter station dumping the sinter cake from the pan for further processmg.

References Cited in the file of this patent UNITED STATES PATENTS 1,245,183 Boynton Nov. 6, 1917 1,656,115 Holmberg Jan. 10, 1928 2,367,262 Brassert Jan. 16, 1945 2,578,426 Holmberg Dec. 11, 1951 2,675,223 Rolfsen Apr. 13, 1954 2,763,479 Huisken et a1. Sept. 18, 1956 

1. AN APPARATUS FOR PRODUCING ORE SINTER COMPRISING A CHARGING STATION, A PLURALITY OF SINTERING STATIONS VERTICALLY DISPOSED ONE OVER THE OTHER AND EACH OF SAID SINTERING STATIONS HAVING AN IGNITER AND A SUCTION EXHAUST CONNECTION, A CHARGING ELEVATOR COMMUNICATING WITH THE SAID CHARGING STATION AND EACH OF THE SAID SINTERING STATIONS, A DISCHARGING ELEVATOR COMMUNICATING WITH THE CHARGING STATION AND EACH OF THE SAID SINTERING STATIONS, A PLURALITY OF SINTERING PANS EACH CAPABLE OF BEING ACCOMMODATED BY THE SAID SINTERING STATIONS AND SAID CHARGING AND DISCHARGING ELEVATORS, AND A PAN DUMPING STATION ADJACENT THE SAID DISCHARGING ELEVATOR AND COMMUNICATING WITH THE SAID DISCHARGING ELEVATOR. 